Clock, watch, and the like timekeeping instrument



A. JARRED.

CLOCK, WATCH, AND THE LIKE TIMEKEEPING INSTRUMENT.

' APPLICATION FILED JULY 29,1920.

1,389,666. PatntedSept. 6,1921.

2 SHEETS-SHEET T- A. JARREU.

CLOCK, wATcmANn THE LIKE TIMEKEEPING INSIRUMENT.

APPLICATION FlLED JULY 29. 1920.

H 6 7 M d \M 3 i W e Mm \i i Pia w n Q 4 z w PATENT OFFICE.

, ARTHUR JABRED', or LONDON,'ENGLAND.

CLOCK, warren; Ann T E LIKE .TIMEKEEPING INSTRUMENT.

' Application flled July 29,

To an echo m, it may concern:

Be it known that I, ARTHUR JARRED, a

subject of the King of Great Britain and e Ireland, residing at London, England, have invented certain new and useful Improvements in and Relating to Clocks, Watches, and the like Timekeeping Instruments, of which; the following is a specification.

"This invention relates to improvements in clocks, watches, and the like time keeping instruments. 3v

The invention refers more particularly to improvements in clocks, watches and the like ofthe kind, in which the dial is pro.- vided with twenty four indicating numerals,- to represent the hours, in lieu of the more usual .form in which only twelvehour indicating numerals are used.

In clocks, watches and the like in which the dial is provided with twenty four hour indicating numerals with subdivisions to represent minutes, the numerals, unless con-.

siderably reduced, or the dial is enlarged, are of necessity,'-clo'sely spaced, and consequently lead'to confusion,-

The object Ofitl'lB present invention is to enable,in thistype of clock, watch or the like, numerals'of usual size to be employed, without thenecessity of increasing the size of the dial, and yet at the same time overcoming the objection of confusion between the'numerals.

Another object is to enable the usual clock or watch movement designed for 12 hour periods to be used with the 24 hour indications without alteration in said movement. According to the present invention a dial having the hour-indications arranged to form two sets, one set representing the hours from 1 to 12, and theother the hours from l3 to 2a is disposedbehind a second or masking dial provided with windows corresponding in number to the number of indications forming a set, and means, areprovided for effecting a relative movement between the dials to enable either one or the 'otherset of indicationsto be exposed by the apertures, according to the period of the 24 hour-day in question. I

V \ccording to the invention moreover the means for effecting the relative movement between the dia'lswmay be automatic, and may be operable b the driving "mechanism for the clock, watch or the'lik a. In the drawings, in :which similar refer- Specification of Letters Patent.

' edge viewof a modified form Patented Sept. 6, 1921. 1920. Serial No. 399,813.

ence numerals indicate corresponding parts throughout thefigures; Figure 1 isa'face view of a watch, partly in section, illustrating one form of the'invention in'which the change of the hour indications is effected manually,

Figs. 2 and 3 being a face vi'ewand an I of masking d1al for use therewith.

F 1g. 4 is a side sectional elevation of a clock and Fig. 5 a front elevation thereof with part of the dialbroken away to expose one form of mechanism for changing the hour indications automatically.

Figs. 6, 7, and 8 being detail views of part of the automatic hour indicating changing means in different positions.

Fig. 9 isa front elevationof part of a clock with the dial broken awayto show a modified form" of automatic means for changing the hour indications.

Figs. 10, 11 and 12 being detail views of part of said automatic hour indication changing means in different positions.

Fig. 13 is an enlarged face view of a watch with the dial broken away to show a similar form of automatic hour indication chalngging means to that shown in Figs. 10 to' In the simple form of the invention shown in Figs. 1 to 3 a watch is provided with a primary dial 25. and a secondary or masking dial or mask '26. The primary dial 25 bears two sets of hour indications 1to 12 and 13 'to 24 respectively. The hour indications of the two sets are equally spaced around the'dial 25, but the hour indications of one set arealternately arranged in relation to those ofthe other set. The primary dial 25 is capable of an oscillatory move* ment about its center, the dial 25 being mounted freely on the spindle 36 of'the hour hand '28. It is provided with convenient means for effecting'such oscillation, for instance, a small finger piece 29 projecting an oscillatory movement in the opposite di rection exposing the hour indications 13 to 24 and masking the other 1 to 12. The user will effect the change of the hour indications manually at an adequate time for example when the minute hand 33 passes the half-hour at 12.30 and 24.30 respectively. The windows 32'may be apertures in the masking dial 26 as indicated in Fig. 1 or may be merely transparencies that is to say portions of a transparent dial 26 which is rendered opaque by painting, gilding or otherwise, except at the windows 32 as indicated in Figs. 2 and The clock illustrated in Figs. 4 and 5 is provided with one form of means for effecting the change 01 the hour indications automatically. The clock case 34 contains clockwork mechanism ofany usual typewell known in the art, and is either mechanically or electrically operated, a mechanically operated mechanlsm being shown more. or less dlagrammatlcally as its particular iorm does not constitute an essential part of the-inven-.

tion and needs no description here beyond the indication that 35 is the usual minute hand spindle, 86 the hour hand spindle, and 37, 38, 39, 40, the usual train of gear wheels which effect the. reduction of 12 to 1 in the driving of the hourhand spindle;

A small gear wheel 41 on the hour hand spindle 36 meshes with a-wheel 42 of double the size, so that the said wheel 42 makes half a rey'olution for each revolution oi the hour hand 28. The wheel 42 is mounted on a spindle 43, suitable carried by the clock frame 44. A wheel 45 fixed on the spindle 43 meshes with another wheel 46 01 the same size mounted on a spindle 47 suitably carried by the clock frame 44. Cams 48 and 49 are mounted on the spindles 43 and 4'? respectively and in consequence of the gear wheels 45 and 46. these two cams rotate at the same speed in opposite directions and also at half the speed of the hour hand whereby, for reasons which will be clear hereaften they cfl ect certaln'operations at 12 hour periods. In the particular example.

shown inlligs. 4 and 5 the'primary dial 25 is in the form of a spoked wheel It 18 providcd on one of its spokes with a tappet 5,0,

this particular spoke being omitted in Fig. 5 to expose the parts behind it. The tappet 5O bears alternately; on the cams 48,49, so that the primary dial 25 is held thereby steady in one or the other of the two positions of adjustment with one or the other set or hour indications 1- to 12 or 13 to 24 respectively exposed at the windows 32 in the masking dial 26.- The cams 48, 49, have projections 51, 52, respectively. These proj ections engage respectively with springs 53, 54, soas tojtension the same. The springs 53, 54 as shown maybe for convenience the two ends of the same piece of steel wire coiled about the hub 55 of the primary dial As will be seen from an inspection of Figs. 5 to 8, the cams 48, 49 are set in opposite relation, consequently when one cam is tensioning a spring the other is holding the" tappet and therefore "the dial steady. such condition is illustrated by Fig. 6 wherein the projection 51 on the cam 48 is tensioning the spring 53, while the cam 49 is holding the tappet 50 and therefore the primary dial 25 "steady against the action of the spring 53, the dial 25 being then in the positioncorrespondingto the exposure off-the hour indications 1 to 12. -When the 32, this action occurring at half an hour after noon. The cams 48, 49 will then continue to rotate, the projection 52 on the cam 49 ultimately engaging with and tensioning the spring 54 and the cam 48 holdi-n the tappet 50 and therefore the primary dia l 25 steady, until the parts, at about half an hour after midnight,'reach the position indicated in Fig. 8, wherein the spring 54 is fully tensioned and the tappet 50 is just about to be released by the larger part or. rise of the cam 48 to permit of the spring oscillating the primary dial .25 to change the hour indications at "the windows 32, namely to remove the indications 13 to 24 and expose the indications 1- to 12.

In theiorm of the invention shown in Figs 9- to 12 a single cam 48 is used, the prin'iary dial25 being provided with two tappets 50, 50, adapted to bear ondiametrically oppositesidcs of the-cam sothat they are releasedalternately, the. springs 53, 54 hearing alsodiametrically on opposite sides 01 the cam so that they are alternately tensioned. The action is similar to the foregoing example. In F ig; 9 the primary dial is in the "position in which it exposes the hour indications 13 to .24, andthe cam 48 is just about to releasethe tappet 50 to pennit the teusioned spring-Z53 to oscillate the primary dial to expose the hour indications 1 to 12, the cam and allied parts being shown in this position in Fig. 10. A later condition is shown in Fig. 11, while in Fig; 12 the tappet 50" is just about to be released to permit the tensioned spring 54 to oscillate the primary dial to expose attain the'hour indications 13'to 24. In Fig. 13 a'similar form of the invention to that last described is shown appliedito a watch the action being identical so that, no further description is necessary, the corresponding parts being indicated by similar reference numerals.

- mary dial bearing two sets of hour indica- I claim: A time keeping instrument having a pritions, a masking dial to expose either of said hour indications and conceal the other in accordance with the position of the primary dial relative to the masking dial, 0pposed springs carried by the primary dial and each operative when tensioned to move the primary dial in a direction responsive to such tension,ac am formed to directly engage and tension said springs in succession at periodic intervals, and members carried by the primary dial to be held by said cam against permitting movement of the pri- 15 mary dial under the spring influence until one of said members and said cam are in a determinate relative position.

In testimony whereof I have signed my name to this specification.

ARTHUR J ARRED. 

